Structure and method for compaction of powder-like materials

ABSTRACT

Structure and method for producing very dense bodies of material from particulate materials. A particle material is placed within an electrically conductive container. A solenoid or coil encompasses the electrically conductive container, and a large magnitude of electrical current is caused to flow through the solenoid or coil. As the electrical current flows through the solenoid or coil, large magnitudes of magnetic pressures are created upon the electrically conductive container, and the electrically conductive container is compressed, and the transverse dimension thereof is reduced. Thus, the particulate material within the electrically conductive container is firmly compacted, and a rigid body of material is provided. Any one of numerous types of particulate material may be employed. A method and system for selecting various parameters which enable the material to be densified to densities in excess of 90% of the material&#39;s maximum density is also illustrated in another embodiment of the invention.

RELATED APPLICATION

This application is a division of application Ser. No. 08/681,898 filedJul. 29, 1996, now U.S. Pat. No. 6,273,963 which is acontinuation-in-part of application Ser. No. 08/368,301 filed Jan. 3,1995, now issued as U.S. Pat. No. 5,611,230, which is a division of Ser.No. 07/834,148 filed Feb. 10, 1992, now issued as U.S. Pat. No.5,405,574.

BACKGROUND OF THE INVENTION

Several methods have been employed for forming particulate orpowder-like materials into a unitary firmly compacted body of material.

Powdered metal bodies have been formed by means of pressure and heat.Such a method has also been used for forming unitary bodies from otherpowder or particulate materials.

A problem has specifically existed with regard to formingsuperconducting powders into a unitary firmly compacted body. Ceramicsuperconducting powders are normally prepared by proportioning thespecific quantities of selected oxides. The combination is thenthoroughly mixed by conventional means and then fired at elevatedtemperatures in suitable gaseous atmospheres. The induced solid statereaction causes the formation of the desired ceramic compositions andlattice structures.

In ceramic superconductors, the superconductivity within individualcrystallites is proximity coupled to neighboring grains. Consequently,the orientation and coupling between crystallites are key factorsaffecting the current carrying capacity of the bulk ceramicsuperconductors. Voids, cracks, and grain boundaries act as weak linksbetween crystallites and reduce the critical currents within the bulkmaterial. Therefore, a technique which produces dense ceramics with goodintergrain coupling and by which the material is formable into desiredshapes to yield a required superconducting characteristic is ofsignificant value.

At the present time several methods are used for obtaining high criticalcurrent densities in bulk superconducting materials.

One method employed is that of melt textured growth of polycrystallingmaterial. This method is discussed in a paper included in Volume 37, No.13, May 1, 1988, Physical Review B., S. Gin, et al., entitled:Melt-Textured Growth of Polycrystaline. This method consists of heatinga bulk specimen of the high temperature material in a furnace totemperatures at which partial melting occurs. A temperature gradient ismaintained in the furnace, and the superconductor is melted andrecrystallized as the specimen is passed through the hot zone. Highlytextured material is produced through this method and at present isshown to yield high Jc values. This method is generally limited to theprocessing of small length samples.

Another method is that of placing powder in a tube. This “powder intube” method is discussed in a paper 1989 Applied Physics Letters, page2441, prepared by K. Heine, et al., entitled: High-Field CriticalCurrent Densities. In the “powder in tube” method, mechanicaldeformation is used to align plate-like particles of bismuth basedsuperconductors. The powder is loaded into a tube of silver material andthe assembly is compacted by swaging, drawing or rolling. A silversheath provides a path to shunt currents across any defects. Thematerial is subsequently heat treated to obtain the optimumsuperconductor characteristics.

However, as a result of the nature of varied mechanical operationinvolved in the two methods discussed above, reproducing the manyprocessing steps repeatedly during fabrication of long lengths of wiresand tapes remains unsatisfactory.

Another method of compaction is that of hot extrusion. This method isdiscussed in an article entitled: Hot Extrusion of High-temperatureSuperconducting Oxides by Uthamalingam Balachandran, et al., AmericanCeramic Bulletin, May 1991, page 813.

Another method is discussed in U.S. Pat. No. 5,004,722, Method of MakingSuperconductor Wires By Hot Isostatic Pressing After Bending.

Another compaction techniques which has been employed pertains to ashock method. This method is discussed in an article entitled:Crystallographically oriented superconducting Bi ₂ Sr ₂ CaCu ₂ O ₈ byshock compaction of prealigned powder by C. L. Seaman, et al., inApplied Physics Letters 57, dated Jul. 2, 1990, page 93.

Another method of compaction is that known as an explosive method,discussed in an article entitled: Metal Matrix High-TemperatureSuperconductor, by L. E. Murr, et al., in Advanced Materials andProcesses Inc. Metal Progress, October 1987, page 37.

These methods are limited in value because they are generally applicableonly to production of small body sizes.

The application of large uniaxial static pressures at elevatedtemperatures is discussed in an article entitled: Densification of YBa ₂Cu ₂ O ₇₋₈ by uniaxial pressure sintering, by S. L. Town, et al., inCryogenics, May 1990, Volume 30.

The use of electromagnetic forming for the purpose of attachment isdiscussed in a paper entitled: Electromagnetic Forming, by J. Bennettand M. Plum, published in Pulsed Power Lecture Series, Lecture No. 36.

However, processing of long lengths of homogenous and high qualitysuperconducting tapes or wires by the processes discussed above has notbeen realized.

It is an object of this invention to provide a method and means forproducing high density bodies by the use of powder-like and/orparticulate materials.

It is another object of this invention to provide a method and means forproducing electrical conductors by the use of powder-like or particulatematerials.

It is another object of this invention to provide a method and means forproducing high quality and continuous superconducting electricalconductors such as wires and tapes.

It is another object of this invention to provide such a method whichcan be consistently precisely duplicated in the quality of production.

Another object of the invention is to provide a method for magneticallycompacting a powder to achieve in excess of 90% of its maximum densityusing applied pressures which have heretofore not been able to achievesuch densities.

Another object of the invention is to provide a method and system forselecting various variables which enable the system and method tocompact a material to a density which exceeds densities normallyachieved with a given applied input pressure.

Still another object of the invention is to provide a method and systemfor accelerating a wall of a container for compacting a material todensities in excess of 90% of that material's maximum density.

Other objects and advantages of this invention reside in theconstruction of parts, the combinations thereof, and the methodsemployed, as will become more apparent from the following description.

SUMMARY OF THE INVENTION

In this invention, powder-like and/or particulate materials or the likeare compacted into high density bodies. The high density bodies can beof various shapes and sizes, and may, for example, be bodies such asrods, tapes, tubes, or plates or any other suitably shaped or desirablyshaped bodies.

The method and structure of this invention applies pressures generatedby noncontact electromagnetic forces. These electromagnetic pressuresare generated by employing suitably shaped coils, such as solenoids orthe like which have the necessary current carrying capacity. In thisprocess a suitable electrically conductive container is encompassed bysuch a coil or solenoid. Within the electrically conductive containerpowder-like material is enclosed. When high magnitudes of electricalcurrent are passed through the solenoid or coil, very high pressures areapplied to the electrically conductive container, and the electricallyconductive container is reduced in transverse dimensions. Thus, thepowder-like material within the electrically conductive container iscompacted into a body of high density.

In one embodiment of this invention superconducting powders are placedupon an electrically conductive strip, and the strip is formed into atubular member, thus enclosing the superconducting powders. The tubularmember is encompassed by a solenoid or coil. High current levels arepassed through the solenoid or coil, and a high magnitude of resultingelectromagnetic pressure is applied to the tubular member. Thetransverse dimensions of the tubular member are significantly reducedand the superconductive powder within the tubular member is thus firmlycompacted. If desired, this process can be performed in a continuousmanner, so that an elongate conductor of superconductive material isproduced. The compaction method of this invention is capable ofproducing wire or tape of normal electrical conducting material or ofsuperconducting electrical materials.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIG. 1 is a perspective diagrammatic view illustrating a structure and amethod of compaction of powder-like materials in accordance with thisinvention;

FIG. 2 is a perspective diagrammatic type of view illustrating a methodand structure in accordance with this invention for producing in acontinuous process an elongate member, which may be referred to as awire, or tape, or the like. The process illustrated can be employed forproduction of an elongate member of superconductive material;

FIG. 3 is a perspective diagrammatic view illustrating a structure and amethod of compaction of powder-like materials in accordance with anotherembodiment of the invention;

FIG. 4 is a cross-sectional view of an armature showing a powder-likematerial situated therein and also showing a stand-off distance betweena wall of a container and the material;

FIG. 5 is a schematic diagram of a method and process for compacting amaterial according to the invention;

FIGS. 6A-6C are various graphic views illustrating various correlationsbetween time, container wall displacement, container wall velocity andpressure applied by container wall to a material situated within thecontainer; and

FIGS. 7A-7C illustrate further correlations associated with theinvention and particularly an “overpressure” realized by a materialcompacted in accordance with this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows direct current power supply 20 to which is connectedelectric conductors 22 and 24. Connected to the conductor 22 is a switch26 which is also connected to a conductor 28. The conductor 28, and theconductor 24 have joined therebetween a capacitor 30. The conductor 28is also connected to a switch 32 which is also connected to a conductor34. The conductor 24 and the conductor 34 are connected to a solenoid orcoil 36 which encompasses an electrically conductive container 38. Theelectrically conductive container 38 is shown as being rectangular intransverse dimensions. However, the electrically conductive container 38may be of any suitable or desired shape and size. The electricallyconductive container 38 may be of any suitable electrically conductivematerial, such as, for example, of silver material.

Within the electrically conductive container 38 is a quantity of powdermaterial 40. The powder material 40 completely fills the electricallyconductive container 38 and is firmly positioned therewithin.

In carrying out the process of this invention, the switch 26 is closed,and the capacitor 30 is charged from the power supply 20. After thecapacitor 30 is completely charged, the switch 26 is opened and theswitch 32 is closed. When the switch 32 is closed a large quantity ofelectrical current flows from the capacitor 30 through the solenoid orcoil 36. When electrical current flows through the coil or solenoid 36magnetic pressure is applied upon the electrically conductive container38. This pressure acts inwardly upon the electrically conductivecontainer 38, and the transverse dimensions of the electricallyconductive container 38 are reduced. Thus, compression occurs within theelectrically conductive container 38, and the powder-like material 40within the electrically conductive container 38 is compressed andcompacted. Thus, the powderous material 40 within the electricallyconductive container 38 becomes a dense body.

As an example or illustration, the electrically conductive container 38may have a transverse dimension of less than one inch or several inches,and current flow through the solenoid 36 may be in the order of about100,00 amperes at a voltage of about 4,000 volts. It is to beunderstood, of course, that other magnitudes of current may be employedas found to be suitable in accordance with the size and physicalcharacteristics of the electrically conductive container 38 and thephysical characteristics and volume of the powder-like material 40. Itis also to be understood that when the powder-like material 40 has goodelectrically conductive properties, the-container thereof may not needto be electrically conductive for compaction of the powder-like materialin accordance with the method of this invention. Due to the fact thatthe solenoid or coil 36 tends to expand radially as current flowstherethrough, suitable means are employed to restrain the coil 36against lateral expansion as current flows therethrough. For example, asshown, a rigid wall 44 closely encompasses the coil 36 and restrains thecoil 36 against expansion as current flows therethrough.

FIG. 2 illustrates structure and a method of the construction of anelongate body, such as a wire or tape or rod in accordance with thisinvention. A strip of electrically conductive material 50 in a flatcondition is moved longitudinally as illustrated by arrows 52. Apowderous material 54 having desired physical or electrical propertiesis poured upon the strip 50. When a superconductive body is desired, thepowderous material 54 is superconductive material. Thus, the strip 50carries the powder-like material 54.

Then be any suitable means, such as by means of a forming unit 55, thestrip 50 is formed into a tubular member 50 a, as the tubular member 50a encloses and carries the powder-like material 54. Then the diameter ofthe tubular member 50 a is reduced as the tubular member 50 a is drawnthrough a drawing unit 57. Thus, the diameter of the tubular member 50 ais reduced as elongation of the tubular member 50 a occurs. Thus, adegree of compaction of the powder-like material occurs as drawing andelongation of the tubular member 50 a occurs.

Then the tubular member 50 a is moved into the confines of a solenoid ora coil 56. The coil 56 is energized form a power source 60. Electricalconductors 62 and 64 are connected to the power source 60. Joined to theconductor 64 is a switch 66. A conductor 67 is also connected to theswitch 66. Connected to the conductors 62 and 67 is a capacitor 68. Alsoconnected to the conductor 67 is a switch 72. Also connected to theswitch 72 is a conductor 74. The conductor 74 and the conductor 62 arejoined to the solenoid or coil 56.

In accordance with the method of this invention, the capacitor 68 ischarged form the power source 60 as the switch 66 is closed. Then theswitch 66 is opened, and the switch 72 is closed so that a largemagnitude of current flows form the capacitor 68 through the coil orsolenoid 56, as illustrated by arrows 76. The flow of current throughthe coil 56 may be in the order of several thousand amperes. Then thisflow of current through the solenoid or coil 56 occurs a high magnitudeof magnetic pressure is applied to the tubular member 50 a. The pressureupon the tubular member 50 a causes reduction of the transversedimension of the tubular member 50 a. Thus, the powder material 54within the tubular member 50 a becomes very firmly compacted. Due to thefact that the coil 56 tends to expand during current flow therethrough,a wall 80 closely encompasses the coil 56 and restrains the coil 56against radial and axial expansion.

If desired, after the tubular member 50 a passes through the electricalcoil 56, the tubular member 50 a, with the powderous material 54compacted therewithin, may pass through a sintering operation 84. Thesintering operation 84 improves the properties of the compactedpowder-like material 54. Power driven roller means 85 are shown formoving the tubular member 50 a.

By this means and method, a desired elongate body can be produced. Bythis means and method superconducting wire or tape or the like can beproduced. As illustrated, the process can be a continuous process. Bycontinuously moving the tubular member 50 a through the solenoid 56while current flows through the solenoid 56, continuous lengths of tubesare compacted, and a continuous length of electrical conductor ofsuperconducting material is produced. Thus, superconductors of anydesired shape and size and/or length can be produced in a singleoperation or in a continuous operation or in plurality of operations.Long lengths of superconducting material can be repeatedly and preciselyproduced by this non-contact method. After processing, the wire ofsuperconducting material may be wound into a coil 86, as shown in FIG.2.

The method and structure shown in FIG. 2 have been found to besuccessful in creating a wire-like conductor of superconductingmaterial. As an example or illustration, a wire of superconductingmaterial was produced in which the strip 50 was approximately one-halfinch in width and approximately fifteen thousandths of an inch inthickness. The superconductive powder material 54 employed wasBi(Pb)SrCaCuO. The current flow through the coil 56 was in the order ofabout one hundred thousand amperes. After travel through the coil 56 thetransverse dimension of the tubular member 50 a was about one-eighth ofan inch.

Referring now to FIGS. 3-7C, another embodiment is shown. It should beappreciated that those parts which operate in the same manner as theparts illustrated in FIGS. 1 and 2 have been identified with the samepart number except that a “′” has been added thereto.

As best illustrated in FIG. 3, a direct current power supply 20′ iscoupled to a pair of electric conductors 22′ and 24′. Connected toconductor 22′ is a switch 26′ which is also connected to a conductor28′. The conductor 28′ and the conductor 24′ have joined therebetween acapacitor 30′. The conductor 28′ is also connected to a switch 32′ whichis also connected to a conductor 34′. The conductor 24′ and theconductor 34′ are connected to a solenoid or coil 36′ which encompassesan electrically conductive container 100′ as shown as being generallycylindrical in transverse dimensions. However, as mentioned earlierherein, the electrically conductive container 100′ may be any suitableor desired shape and size. The electrically conductive container 100′may be of any suitable electrically conductive material such as, forexample, of silver or copper material.

Within the electrically conductive container 100′ is a quantity ofpowder 102′. The powder 102′ fills the electrically conductive container100′ to a desired fill level until a predetermined fill density isachieved. For example, in the illustration being described thepredetermined fill density may be on the order about 3.7 grams per cubiccentimeter for a ferrous powder. As best illustrated in FIG. 4, it mayalso be desired to provide a predetermined stand-off distance 106′between the inside of a wall diameter 108′ and powder 102′. It has beenfound that providing some predetermined stand-off distance facilitatesaccelerating the wall 108′ of container 100′ as the wall 108′ expandsradially (as viewed in FIG. 4) to compress powder 102′. The process andoperation of this embodiment is substantially the same as the embodimentdescribed earlier herein. Namely, the switch 26′ is closed, and thecapacitor 30′ is charged from the power supply 20′. After the capacitor30′ is completely charged, the switch 26′ is opened and the switch 32′is closed. When the switch 32′ is closed a large quantity of electricalcurrent flows from the capacitor 30′ through the solenoid or coil 36′.When electrical current flows through the coil or solenoid 36′, magneticpressure is applied upon the electrically conductive container 100′.This pressure acts similarly upon the electrically conductive container100′, and the transverse dimensions of the electrically conductivecontainer 100′ are reduced. Thus, compression occurs within electricallyconductive container 100′, and the powder-like material 102′ within theelectrically conductive container 100′ is compressed and compacted.Thus, the powderous material 102′ within the electrically conductivecontainer 100′ becomes a dense body.

As with the embodiment described earlier herein, solenoid or coil 36′tends to expand radially as current flows therethrough. Accordingly,means are employed to restrain the coil 36′ against lateral expansion ascurrent flows therethrough. For example, as with the first embodiment, arigid wall 44′ closely encompasses the coil 36′ and restrains the coil36′ against expansion as current flows therethrough.

As best illustrated in FIG. 5, a process or method for compactingmaterial 102′ in accordance with the second embodiment of this inventionwill now be described. Initially, the powder material 102′ is selected(block 108′ in FIG. 5) and a density for container 100′ is determined atblock 110′. As an illustration, a density associated with container 100′may be about 9,000 Kg/M3.

Once the density and thickness of wall 108′ of container 100′ isdetermined, the fill density and a compressibility value for powder 102′is determined at block 112′. In this regard, the fill densitycorresponds to the density of the material after it is situated incontainer 100′ and before it is compacted in accordance with thisinvention. The compressibility value for material 102′ corresponds tothe ease or difficulty with which the material 102′ compacts.

At block 114′, the stand-off distance corresponding to the distancebetween an inside surface or diameter 108 a′ and powder 102′ isdetermined. As mentioned earlier herein, it has been found thatproviding this stand-off distance 106′ can facilitate enabling wall 108′to “over-pressure” 102′ and achieving high compaction densities, asdescribed later herein.

For ease of illustration, the method and apparatus will be describedwith the material 102′ being a ferrous powder. The density and thicknessof wall 108′ were selected to be 8.96 grams/CM3 and about 1.0millimeter, respectively. The fill density for material 102′ wasselected to be 3.79 g/CM3 and the stand-off distance 106′ (FIG. 4) wasselected to be zero.

After container 100′ density and thickness are determined and the filldensity, compressibility value for material 102′, and the stand-offdistance 106 for material 102′ are determined, the container 100′ isfilled with the material 102′ (block 116′).

At block 118′, a power supply 20′ is set to an appropriate currentlevel, which in the illustration being described may be on the order ofabout 100,000 amperes at a voltage of about 4,000 volts. It is to beunderstood, of course, that other magnitudes of current and voltage maybe employed as found to be suitable in accordance with the size andphysical characteristic of the electrically conductive container 100′and the physical characteristics and volume of the material 102′ as withthe embodiment described earlier herein.

After the current level is selected, the solenoid 36′ is energized tomagnetically pressure the electrically conductive container 100′ tocompact material 102′ (block 120′ in FIG. 5).

At decision block 122′, it is determined if more or repeated compactionof material 102′ is desired. If it is, then the method loops back toblock 116′ as shown, otherwise the routine is complete. If it is not,then the routine proceeds to block 124′ where the compacted material102′ may be subject to further processing, such as the sinter operation84 described relative to the embodiment mentioned above. Afterprocessing, the wire of material may be wound into a coil 86 of the typeshown in FIG. 2.

Advantageously, this method and system described relative to thisembodiment provides means for magnetically compacting a material byoverpressuring the material such that it is compacted to comprise adensity of at least 90% of the maximum density of powder 102′. Further,by selecting and adjusting the various variables, such as the densityand thickness of wall 108′ of container 100′, fill density andcompressibility value for material 102′ and stand-off distance 106′, thematerial 102′ can be compacted in a manner such that the material 102′receives a pressure which is far in excess of the initial pressureapplied by container 100′.

FIGS. 6A-6C illustrate various features achieved by this invention. Inthis regard, notice FIG. 6A illustrates a correlation between the timecontainer 100′ is energized relative to the pressure applied by wall108′ to material 102′. Notice the sharp peak at 110′ in FIG. 6A whichindicates a maximum applied pressure on material 102′ of about 5×108 Pa.

FIGS. 6B and 6C illustrate the correlation between the displacement ofwall 108′ during the energization process (FIG. 6B) and the velocity ofwall 108′ as it expands radially to compress material 102′. Notice inFIG. 6C that as the time approaches approximately 3 by 10-5 seconds, amaximum velocity (FIG. 6C) of wall 108′ is realized and the material102′ displaces (FIG. 6B) as it is compacted. Correlating this to FIG.6A, it should be appreciated that the wall 108′ achieves a radialvelocity of about 200 meters per second in less than about 3×10-5seconds as the applied pressure reaches a maximum 100′ (FIG. 6A).

Notice in FIG. 7A a correlation between an applied pressure curve 112′and a material pressure curve 114′ representing the pressure experiencedby material 102′ as it is compacted. As the pressure experienced bymaterial 102′ exceeds the maximum applied pressure, indicated by point110′, an “overpressure” pressure (represented by double arrow 118′ inFIG. 7A) is realized. Because the overpressure far exceeds the maximuminput pressure 110′ applied by container 100′, the material 102′ may becompacted to density levels which exceed the levels normally realizedwith the associated input pressure.

Thus, it should be appreciated that by adjusting one or more of thevariables mentioned earlier herein relative to blocks 108-114 (FIG. 5),the material 102′ can be over-pressured to achieve pressures far greaterthan the input pressure applied by wall 108′ (FIG. 4) of container 100′.This, in turn, enables the apparatus and method of the present inventionto densify material 102 to densities in excess of 90% of the material'smaximum density or far in excess of densities achieved in response tothe maximum applied pressure 110′.

It has been found that these densities have been achieved byaccelerating container 100′ and energizing coil or solenoid 36′ in lessthan 500 or even 100 microseconds.

In this regard, notice in FIGS. 7B and 7C that the overpressuring ofmaterial 102 in accordance with this method and apparatus enables thematerial 102′ to be densified to in excess of 7500 Kg/M2 with anassociated input pressure of only 5×108 Pa.

FIG. 7C further illustrates a correlation between the pressure appliedby container 100′ and the density realized by material 102′, with theadditional density associated with the achieved overpressure beingrepresented by double arrow 120′ in FIG. 7C.

Advantageously, this method and system provide dynamic means foraccelerating wall 108′ of container 100′ such that the material 102′experiences a pressure which is significantly higher than the inputpressure applied by wall 108′. It has been found empirically that thetime at which the overpressure pressure 120′ (FIG. 7C) varies directlywith either the thickness or the density of wall 108′. For example, asthe thickness of wall 108′ increases, the overpressure 120′ alsoincreases. Likewise, the peak pressure 116′ has also been found toincrease or decrease when the fill density increases or decreases,respectively.

This system and method also provide means for selectively varying someof the input parameters, such as wall thickness and density, stand-offdistance, container mass and the like to achieve densities in excess of90% of the materials maximum density. For example, by increasing thethickness and mass of wall 108′, the corresponding velocity required toachieve a predetermined density is decreased when compared to acontainer having less thickness or mass.

It is to be understood that the method of this invention can be employedin compacting most types of powder-like or powderous materials, such asceramic compounds, ceramic and metal composites, metals, metal alloys,and metal compounds.

Although the preferred embodiment of the structure and method forcompaction of powder-like materials of this invention has beendescribed, it will be understood that within the purview of thisinvention various changes may be made in the electrical circuitry and inthe current flow therethrough, or in the form, details, proportion andarrangement of parts, the combination thereof, and the method ofoperation, which generally stated consist in a structure and methodwithin the scope of the appended claims.

The invention having thus been described, the following is claimed:
 1. Amethod for compacting a powder comprising the steps of: selecting apowder; selecting a container comprising a predetermined density andwall thickness; filling said container with said powder at apredetermined fill density level; situating said container in asolenoid; and energizing said solenoid to accelerate said container toan impact velocity in excess of 100 meters per second in less than apredetermined period to densify said material to a predetermineddensity.
 2. The method as recited in claim 1 wherein said method furthercomprises the step of: filling said container with said powder such thatsaid powder is situated a predetermined stand-off distance from saidcontainer.
 3. The method as recited in claim 1 wherein said methodfurther comprises the step of: applying a predetermined current to saidsolenoid for a pulse duration of less than 150 microseconds.
 4. Themethod as recited in claim 1 wherein said method further comprises thestep of: selecting said container to have a predetermined mass.
 5. Themethod as recited in claim 1 wherein said filling step further comprisesthe step of: determining a compressibility value for said powder;determining a fill density using said compressibility value for saidpowder; and using said fill density to fill said container with saidpowder.
 6. The method as recited in claim 1 wherein said method furthercomprises the step of: determining a standoff distance between saidcontainer and said powder; energizing said solenoid for a predeterminedtime in response to said standoff distance.
 7. The method as recited inclaim 5 wherein said method further comprises the step of: determining astandoff distance between said container and said powder; energizingsaid solenoid for a predetermined time in response to said standoffdistance.
 8. The method as recited in claim 1 wherein said energizingstep further comprises the step of: energizing said solenoid such thatsaid predetermined period comprises an energizing period of less than 40microseconds.
 9. The method as recited in claim 1 wherein said methodfurther comprises the step of: energizing said solenoid to accelerate tosaid impact velocity such that said material is compacted to at least90% of its maximum density.
 10. The method as recited in claim 1 whereinsaid method further comprises the steps of: selecting said containersuch that it comprises a predetermined container thickness; andselecting a powder radius.
 11. The method as recited in claim 1 whereinsaid container is cylindrical in cross-section.
 12. The method asrecited in claim 1 further comprising the step of: energizing saidcontainer to a velocity of at least 150 meters/second in less than 40microseconds.
 13. The method as recited in claim 1 further comprisingthe step of: energizing said solenoid for said predetermined periodwhich is less than 100 microseconds.
 14. A method for magneticallycompacting a powder to a predetermined density comprising the steps of:selecting a container comprising a predetermined mass and wallthickness; situating said powder in said container; and energizing saidcontainer to achieve an impact velocity less than 1,000 microseconds todensify said powder to at least 90% of its maximum density.
 15. Themethod as recited in claim 14 wherein said method further comprises thestep of: accelerating said container to said impact velocity in lessthan 5×10-5 seconds into said powder to compact said material to atleast 90% of its maximum density.
 16. The method as recited in claim 14wherein said impact velocity is at least 100 meters/second in less thansaid 100 microseconds.
 17. The method as recited in claim 14 whereinsaid method further comprises the step of: energizing said containersuch that said container achieves said impact velocity in less than 50microseconds.
 18. The method as recited in claim 14 wherein saidcontainer is generally cylindrical in cross-section.
 19. The method asrecited in claim 17 wherein said impact velocity is between 100 to 200meters/second.
 20. The method as recited in claim 14 further comprising:selecting a container having a mass of at least 9,000 Kg/M3.
 21. Amethod for magnetically compacting a material such that it is compactedto comprise a predetermined material density of at least 90% of itsmaximum density: selecting said material; selecting a container having apredetermined mass; placing the material in said container; energizing acoil to accelerate at least a portion of said container to an impactvelocity to densify said material to said predetermined materialdensity.
 22. The method as recited in claim 21 wherein said methodfurther comprises the step of: determining a mass for said material;selecting a container in response to said mass.
 23. The method asrecited in claim 21 wherein said method further comprises the step of:determining said predetermined mass in response to the material to bedensified; energizing said container such that it is displaced at least0.001 meters in less than about 4×10-5 seconds.
 24. The method asrecited in claim 21 wherein said method further comprises the step ofplacing the material in said container a predetermined standoff distanceand a predetermined fill density.
 25. The method as recited in claim 21wherein said method further comprises the step of: energizing said coilfor a pulse duration of less than 150 microseconds to achieve saidpredetermined material density.
 26. The method as recited in claim 21wherein said method further comprises the step of: determining acompressibility value for said powder; using said compressibility valuefor said powder to determine said predetermined fill density.
 27. Themethod as recited in claim 21 wherein said method further comprises thestep of: determining a standoff distance between said container and saidmaterial.
 28. The method as recited in claim 26 wherein saidoverpressure step further comprises the step of: determining a standoffdistance between said container and said material.
 29. The method asrecited in claim 21 wherein said method further comprises the step of:actuating said container to said impact velocity in less than 50microseconds.
 30. The method as recited in claim 21 wherein said methodfurther comprises the step of: accelerating said container into saidpowder to achieve said density in less than 40 microseconds.
 31. Themethod as recited in claim 21 wherein said container is cylindrical incross-section.
 32. A magnetic compaction system for densifying amaterial to achieve a predetermined density of at least 90% of itsmaximum density, comprising: a container for receiving said material ata predetermined fill density and a predetermined standoff distance, saidcontainer comprising a predetermined mass; an energizer for energizingthe container to accelerate at least a portion of said container to apredetermined velocity to densify said material to at least 90% of itsmaximum density.